In Most states, a death in a home, no matter how it occurred, is not considered a "Material Fact" and it's not required to be disclosed. A murder could have occurred days ago and the seller does not have to let you know.
A death in a home, especially a violent death, can decrease the home's value by 25% and increase its time to sell by up to 50% longer than comparable homes.
Would you want to know that a murder, suicide or even a bizarre death occurred at the property before you sign the contract?